ee2ccb5cb6
Fixes https://github.com/openai/codex/issues/2610 This PR sorts the tools in `get_openai_tools` by name to ensure a consistent MCP tool order. Currently, MCP servers are stored in a HashMap, which does not guarantee ordering. As a result, the tool order changes across turns, effectively breaking prompt caching in multi-turn sessions. An alternative solution would be to replace the HashMap with an ordered structure, but that would require a much larger code change. Given that it is unrealistic to have so many MCP tools that sorting would cause performance issues, this lightweight fix is chosen instead. By ensuring deterministic tool order, this change should significantly improve cache hit rates and prevent users from hitting usage limits too quickly. (For reference, my own sessions last week reached the limit unusually fast, with cache hit rates falling below 1%.) ## Result After this fix, sessions with MCP servers now show caching behavior almost identical to sessions without MCP servers. Without MCP | With MCP :-------------------------:|:-------------------------: <img width="1368" height="1634" alt="image" src="https://github.com/user-attachments/assets/26edab45-7be8-4d6a-b471-558016615fc8" /> | <img width="1356" height="1632" alt="image" src="https://github.com/user-attachments/assets/5f3634e0-3888-420b-9aaf-deefd9397b40" />
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Dependencies
Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this
macOS
Expects /usr/bin/sandbox-exec to be present.
Linux
Expects the binary containing codex-core to run the equivalent of codex debug landlock when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.
All Platforms
Expects the binary containing codex-core to simulate the virtual apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the codex-arg0 crate for details.